Wireless device reconfigurable radiation desensitivity bracket systems and methods

ABSTRACT

A wireless communications device reconfigurable radiation desensitivity bracket, and associated reconfigurable radiation desensitivity method are provided. The method includes: generating a radiated wave at a first frequency; in response to generating the radiated wave at the first frequency, creating a maximum current per units square (I/units 2 ) through a minimal area of an electrical circuit groundplane; generating a radiated wave at a second frequency; in response to generating the radiated wave at the second frequency, maintaining the maximum I/units 2  through the minimal area of the groundplane. Alternately stated, the method controls the distribution of current flow through a groundplane, responsive to radiated emissions, as the wireless device changes operating frequency or communication band. More specifically, the method maintains the maximum I/units 2  through the minimal area of the groundplane by coupling the groundplane to a bracket having a selectable effective electrical length.

RELATED APPLICATIONS

This application is a continuation-in-part application of U.S.application Ser. No. 10/775,722, filed Feb. 9, 2004, now U.S. Pat. No.6,937,195 by Jordi Fabrega-Sanchez, Stanley S. Toncich and Allen Tran,which is hereby incorporated by reference. U.S. application Ser. No.10/775,722 is a continuation-in-part application of U.S. applicationSer. No. 10/120,603, filed Apr. 9, 2002, now U.S. Pat. No. 6,885,341 byJordi Fabrega-Sanchez, Stanley S. Toncich and Allen Tran, which ishereby incorporated by reference, which claims the benefit of U.S.Provisional Application 60/283,093, filed Apr. 11, 2001, which is herebyincorporated by reference.

In addition, this application relates to the following U.S. applicationsand patents, which are hereby incorporated by reference: “ReconfigurableRadiation Desensitivity Bracket Systems and Methods”, filed on the sameday and having the same inventors as the present application; U.S. Pat.No. 6,690,176, issued Feb. 10, 2004, by Stanley S. Toncich, entitled“Low Loss Tunable Ferro-Electric Device and Method of Characterization”;U.S. Pat. No. 6,765,540 B2, issued Jul. 20, 2004, by Stanley S. Toncich,entitled “Tunable Antenna Matching Circuit”; application Ser. No.09/927,136, filed Aug. 10, 2001, by Stanley S. Toncich, entitled“Tunable Matching Circuit”; application Ser. No. 10/076,171, filed Feb.12, 2002, by Stanley S. Toncich, entitled “Antenna Interface Unit”; andapplication Ser. No. 10/117,628, filed Apr. 4, 2002, by Stanley S.Toncich and Allen Tran, entitled “Ferroelectric Antenna and Method forTuning Same”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to wireless communication and, moreparticularly, to wireless communication antennas.

2. Description of the Related Art

The size of portable wireless communications devices, such astelephones, continues to shrink, even as more functionality is added. Asa result, the designers must increase the performance of components ordevice subsystems and reduce their size, while packaging thesecomponents in inconvenient locations. One such critical component is thewireless communications antenna. This antenna may be connected to atelephone transceiver, for example, or a global positioning system (GPS)receiver.

Wireless communications devices are known to use simple cylindrical coilor whip antennas as either the primary or secondary communicationantennas. Inverted-F antennas are also possible. Many conventionalwireless telephones use a monopole or single-radiator design with anunbalanced signal feed. This type of design is dependent upon thewireless telephone printed circuit board groundplane or housing or bothto act as the counterpoise. A single-radiator design acts to reduce theoverall form factor of the antenna. However, the counterpoise issusceptible to changes in the design and location of proximatecircuitry, and interaction with proximate objects when in use, e.g.,placed on a metallic desk, or the manner in which the telephone is held.As a result of the susceptibility of the counterpoise, the radiationpatterns and communications efficiency can be detrimentally impacted.Even if a balanced antenna is used, so that the groundplanes ofproximate circuitry are not required as an antenna counterpoise,radiation pattern and radiation-susceptible circuitry issues remain.

This problem is compounded when an antenna, or a group of antennasoperate in a plurality of frequency bands. State-of-the-art wirelesstelephones are expected to operate in a number of differentcommunication bands. In the US, the cellular band (AMPS), at around 850megahertz (MHz), and the PCS (Personal Communication System) band, ataround 1900 MHz, are used. Other communication bands include the PCN(Personal Communication Network) and DCS at approximately 1800 MHz, theGSM system (Groupe Speciale Mobile) at approximately 900 MHz, and theJDC (Japanese Digital Cellular) at approximately 800 and 1500 MHz. Otherbands of interest are GPS signals at approximately 1575 MHz, Bluetoothat approximately 2400 MHz, and wideband code division multiple access(WCDMA) at 1850 to 2200 MHz.

To dampen the effects of radiation upon proximate circuitry it is knownto attach so-called bracket, or radiation-parasitic, elements to agroundplane. Typically, these “brackets” are used to evenly distributecurrent through the groundplane associated with a radiated wave.Alternately stated, the brackets are used to prevent any particular spoton a circuit board, housing, or keyboard from becoming too sensitive toradiation-induced current. It is difficult, if not impossible, to designa wireless device to minimize the interaction between antenna radiationand susceptible circuitry in every one of its communication bands. As aresult, a conventional design must be optimized for one particularcommunication band, or the design must be compromised to in one or morecommunication bands of interest.

It would be advantageous if the radiation-induced current sensitivity ofa wireless communications device groundplane could be minimized forevery frequency of operation.

It would be advantageous if the radiation-induced current sensitivity ofa wireless communications device groundplane could be tuned in responseto changes in frequency, or in response to one particular groundplanearea becoming too sensitive.

It would be advantageous if wireless communication device radiationdesensitivity brackets could be made reconfigurable, to minimize thesensitivity of proximate circuitry at every frequency of radiation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of the present invention wirelesscommunications device with a reconfigurable radiation desensitivitybracket.

FIG. 2 is a schematic block diagram of the bracket of FIG. 1.

FIG. 3 is a schematic block diagram of a first variation of the bracketof FIG. 1.

FIG. 4 is a schematic block diagram of a second variation of the bracketof FIG. 1.

FIG. 5 is a schematic block diagram of a third variation of the bracketof FIG. 1.

FIG. 6 is a schematic block diagram of a fourth variation of the bracketof FIG. 1.

FIG. 7 is a schematic block diagram illustrating a fifth variation ofthe bracket of FIG. 1.

FIG. 8 is a schematic block diagram of a sixth variation of the bracketof FIG. 1.

FIG. 9 is a schematic block diagram illustrating a seventh variation ofthe bracket of FIG. 1.

FIG. 10 is a schematic diagram illustration some combinations ofseries-connected and parallel-connected FELS.

FIG. 11 is a plan view schematic diagram illustrating a bracket designwhere a plurality of fixed electrical length sections form a matrix ofadjoining conductive areas.

FIG. 12 is a perspective cutaway view illustrating a bracket housingdesign.

FIG. 13 is a perspective drawing illustrating some exemplary FELSvariations.

FIG. 14 is a schematic block diagram of the present invention portablewireless telephone communications device with a reconfigurable radiationdesensitivity bracket.

FIG. 15 is a schematic block diagram of the present invention wirelesscommunications base station with a reconfigurable radiationdesensitivity bracket.

FIGS. 16A and 16B are diagrams illustrating the present inventionbracket redistributing radiation-induced current flow in a groundplane.

FIG. 17 is a flowchart illustrating the present invention method forreconfigurable radiation desensitivity in a wireless communicationsdevice.

FIG. 18 is a plan view drawing of a wireless device display bracketdesign.

DETAILED DESCRIPTION

The present invention describes a wireless communications device with areconfigurable radiation desensitivity bracket that can be added to thegroundplane of a circuit proximate to a radiation source such as anantenna, to minimize the effects of radiation-induced current. Thebracket can be selectively tuned or switched in response to changes infrequency. Alternately considered, the bracket is space-reconfigurableto selectively redistribute current flow through the groundplaneassociated with radiated waves.

Accordingly, a method is provided for reconfigurable radiationdesensitivity in a wireless communications device. The method comprises:generating a radiated wave at a first frequency; in response togenerating the radiated wave at the first frequency, creating a maximumcurrent per units square (I/units²) through a minimal area of anelectrical circuit groundplane; generating a radiated wave at a secondfrequency; in response to generating the radiated wave at the secondfrequency, maintaining the maximum I/units² through the minimal area ofthe groundplane. Alternately stated, the method controls thedistribution of current flow through a groundplane, responsive toradiated emissions, as the wireless device changes operating frequencyor communication band. The method is applicable to wireless deviceelectrical circuitry such as a printed circuit board (PCB) with mountedcomponents, a display, a connector, or a keypad.

More specifically, the method maintains the maximum I/units² through theminimal area of the groundplane by coupling the groundplane to a brackethaving a selectable effective electrical length. The coupling mechanismmay be through a transistor, p/n junction coupling through a PIN diode,selectable capacitive coupling through a varactor diode or ferroelectriccapacitor, or mechanically bridging through a switch ormicroelectromechanical system (MEMS).

Typically, the bracket has a fixed physical length section, in additionto the selectable effective electrical length section to provide acombined effective electrical length responsive to the fixed physicallength and the selectable effective electrical length. Further, thebracket may include a plurality of selectable electrical lengthsections, a plurality of fixed physical length sections, or a pluralityof both section types. The sections may be connected to the groundplane,series connected, parallel connected, or combinations of theabove-mentioned connection configurations.

FIG. 1 is a schematic block diagram of the present invention wirelesscommunications device with a reconfigurable radiation desensitivitybracket. The device 100 comprises a transmitter 102 and an antenna 104connected to the transmitter 102. The wireless device 100 includes anelectrical circuit 106 having a groundplane 108. A reconfigurableradiation desensitivity bracket 108 is coupled to the groundplane 106.Examples of the electrical circuit represented by reference designator104 include components, such as integrated circuits (ICs), transistors,resistors, capacitors, inductors, and the like, mounted on a printedcircuit board (PCB). Electrical circuit 104 can also be a display, aconnector, or a keypad. The invention is not limited to any particulartype of electrical circuit. In some aspects, the groundplane 106 can bethe wireless device housing 110. Although the antenna 104 is typicallythe primary radiation source, the bracket 108 may also be used tocontrol radiation-induced current from a source such as a transistor,resistor, inductor, integrated circuit, or the like (not shown).

Two primary uses of the present invention bracket are for use in aportable or base station wireless communications device, where circuitryis susceptible to radiating elements such as an antenna, transmitter,transmitter component such as a transistor, inductor, resistor, orchanges in the environment around a radiating element, to list a fewexamples. Receiver circuitry, for example, may be susceptible toradiating elements. Another use for the bracket is inmicroprocessor-driven computing devices, such as a personal computer.Here, susceptible circuitry can be protected, using the presentinvention bracket, from a radiation source such as a power supply,high-speed ICs, or network interfaces.

One general purpose of the bracket 108 is to evenly distributegroundplane currents that are generated as a result of radiatedemissions. For this reason, the bracket 108 is termed a radiationdesensitivity bracket, as radiation-generated current flow through agroundplane often makes wireless device transceiver and antennacircuitry susceptible to proximate objects that interrupt and modifycurrent flow patterns. That is, the bracket acts to distribute currentflow so as make the groundplane less susceptible to proximate objects.In other aspects, the bracket can be used to intentionally directradiation-induced current flow to particular areas of the groundplane,for example, to a shielded area of the groundplane that is notsusceptible to proximate objects such as a user's hand or to a wall thatmay temporarily be in close proximity (within the near-field).

FIG. 2 is a schematic block diagram of the bracket 108 of FIG. 1.Generally, the bracket 108 has a selectable effective electrical length200. The electrical length 200 is the measurement of wavelength, orwavelength portion. The electrical length is directly proportional tofrequency, and is modified by the dielectric constant of the materialthrough which the radiated wave travels to reach the bracket 108. Forexample, the bracket may be tuned to have either an electrical length200 a or electrical length 200 b. As can be appreciated by those skilledin the art, the bracket, in combination with the attached groundplane,forms parasitic element that has a radiation susceptance or sensitivitythat is dependent upon the frequency of radiation. That is, theinteraction of a radiated wave with the groundplane/bracket combinationis dependent upon the electrical length of the bracket. Every bracket108 includes a selectable electrical length section 204 having a distalend 206, a proximal end 208, a control input on line 210 to acceptcontrol signals, and a selectable effective electrical length 200responsive to the control signals on line 210. The bracket is termedconfigurable in that it may include switch elements, tunable elements,or both. As explained in detail below, the electrical length of thebracket can be manipulated using either the switchable or tunableelements.

The selectable electrical length section (SELS) 204 can be a couplingelement such as FET, bipolar transistor, PIN diode, ferroelectriccapacitor, varactor diode, or microelectromechanical system (MEMS)switch. The electric length of the SELS 204 is dependent upon more thanjust the physical length 212 of the section. That is, the couplingaction of the SELS 204 includes a reactance or imaginary impedancecomponent that can be varied to change the electrical length. Note, aMEMS switch can be used a variable air-gap capacitor by partiallyclosing the switch.

Returning to FIG. 1, a desensitivity control circuit 111 has an input online 113 to accept frequency selection commands and an output on line210, connected to the selectable effective length section 204. Thedesensitivity control circuit 111 supplies control signals in responseto the frequency selection commands. That is, the desensitivity controlcircuit 111 tracks the frequency selection commands sent to thetransceiver 112 on line 113 and provides control signals to the bracketaccordingly.

In one aspect, the transmitter 102 is a wireless telephone transmitter,part of transceiver 112 that additionally includes a receiver 114. Asnoted above, the transmitter (and receiver 114), or a set oftransceivers 112 (not shown), may operate in a number of differentcommunications bands, such as AMPS or PCS to name just a couple ofexamples. Further, the transmitter 102 may operate in number of channelswithin a particular communication band. Advantageously, the bracket 108can be configured for every frequency of operation.

For example, the transmitter 102 may selectively operate at a firstfrequency and a second frequency. Then, the bracket 108 selectableelectrical length section has a first effective electrical length,selected in response to the transmitter operating at the firstfrequency. The first effective electrical length may operate to evenlydistribute radiation-induced ground current when the transmitter 102operates at the first frequency. Likewise, the bracket 108 SELS has asecond effective electrical length, selected in response to thetransmitter 102 operating at the second frequency. The second effectiveelectrical length may operate to evenly distribute radiation-inducedcurrent in the groundplane when the transmitter operates at the secondfrequency.

FIG. 3 is a schematic block diagram of a first variation of the bracket108 of FIG. 1. In this variation, the bracket 108 further includes afixed electrical length section (FELS) 300 having a distal end 302, aproximal end 304, and a fixed physical length 306. The combination ofthe selectable electrical length section 204 and the fixed electricallength section 300 provides a combined selectable effective electricallength 308 responsive to the control signal on line 210. That is, theoverall electrical length 308 is a combination of the physical length306 of the FELS 300 and the electrical length 200 of the SELS 204, whichmay be physical length, if enabled as a MEMS for example, or areactance, if enabled as a varactor diode for example.

FIG. 4 is a schematic block diagram of a second variation of the bracket108 of FIG. 1. The bracket 108 may include a plurality of selectableelectrical length sections 204. Although three SELS' 204 are shown, theinvention is not limited to any particular number. As shown, the SELS'204 are connected to the groundplane 106.

FIG. 5 is a schematic block diagram of a third variation of the bracket108 of FIG. 1. As shown, the three SELS' 204 are series-connected to thegroundplane 106. Note, although the series of SELS' is shown asopen-connected (unterminated), in other aspects both ends of the bracket108 may be connected to the groundplane 106 or other circuitry (notshown). In other shown aspects not shown, the connections betweenindividual SELS' 204 in the series may be terminated in the groundplane106.

FIG. 6 is a schematic block diagram of a fourth variation of the bracket108 of FIG. 1. As shown, the three SELS' 204 are parallel-connected tothe groundplane 106. In other aspects not shown, both ends of one or allthe SELS' 204 may be terminated in the groundplane.

FIG. 7 is a schematic block diagram illustrating a fifth variation ofthe bracket 108 of FIG. 1. Here, SELS 204 a is connected to thegroundplane 106, SELS' 204 b and 204 c are series-connected to thegroundplane 106, and SELS' 204 d and 204 e are parallel-connected to thegroundplane 106. Note, although each configuration of SELS' 204 is shownas open-connected (unterminated), in other aspects both ends of eachconfiguration may be connected to the groundplane 106 or other circuitry(not shown).

FIG. 8 is a schematic block diagram of a sixth variation of the bracket108 of FIG. 1. In this aspect, the bracket 108 includes a plurality offixed electrical length sections 300. As shown, two FELS' 300 areseries-connected through an intervening SELS 204. Note, although theseries of sections is shown as open-connected (unterminated), in otheraspects both ends of the bracket may be connected to the groundplane 106or other circuitry (not shown), or the connections between sections maybe terminated in the groundplane 106.

FIG. 9 is a schematic block diagram illustrating a seventh variation ofthe bracket 108 of FIG. 1. As shown, FELS 300 a and 300 b areparallel-connected to the groundplane 106 through separate SELS' 204 aand 204 b, respectively. Alternately, FELS' 300 c and 300 d areparallel-connected through a single SELS 204 c. Note, although eachconfiguration of sections is shown as open-connected (unterminated), inother aspects both ends of each configuration may be connected to thegroundplane 106 or other circuitry (not shown).

FIG. 10 is a schematic diagram illustration some combinations ofseries-connected and parallel-connected FELS' 300.

FIG. 11 is a plan view schematic diagram illustrating a bracket design1100 where a plurality of fixed electrical length sections form a matrixof adjoining conductive areas 1102. For example, the adjoiningconductive areas may part of a wireless device keyboard that is mountedoverlying PCB groundplane 106. The spaces, represented withcross-hatched lines, are the individual keypads. In this aspect, theadjoining conductive areas 1102 are the FELS'. The bracket 1100 alsoincludes a plurality of selectable electrical length sections 204 thatare used to couple between fixed electrical length sections 1102. Avariety of connection configurations are shown, but the examples are notexhaustive of every possible combination. At least one of the selectableelectrical length sections 204 is coupled to the groundplane 106.Alternately, a FELS, enabled as a screw or wire (not shown), forexample, may connect the bracket 1100 to the groundplane 106.

FIG. 12 is a perspective cutaway view illustrating a bracket housingdesign 1200. A housing 1202 surrounds the electrical circuit 104, andfunctions as a bracket element. A third fixed electrical length section300 c is a conductive trace (or conductive paint) formed on the housing1200, coupled to the groundplane 106 through a SELS 204. As shown, SELS204 is connected to a first FELS 300 a, enabled as a conductive trace ofa PCB, a second FELS 300 b, enabled as a screw, connects FELS 300 a to300 c. In other aspects, the FELS 300 b can be a spring-loaded clip,pogo pin, or a conductive pillow (gasket). A variety of other bracketconfigurations are possible that make use of the housing as a bracketelement, as would be understood by those skilled in the art in light ofthe above-mentioned examples.

FIG. 18 is a plan view drawing of a wireless device display bracketdesign. In this aspect the electrical circuit is a liquid crystaldisplay (LCD) 1800 or other type of display circuit. The bracket 108includes a (at least one) selectable electrical length section 204coupling between fixed electrical length sections 300. A plurality offixed electrical length sections 300 form perimeter regions around theLCD 1800. The exact shape of the perimeter is determined by using theSELS' 204 to couple or connect FELS' 300. The perimeter need notnecessarily be closed. As shown the perimeter has an opening 1804. Theopening 1804 placement and electrical length may be tuned used a SELS204 in response to changing transmission frequencies, for example.Further, the opening 1804 may be formed as a result of not switching aSELS 204. Although the perimeter regions are shown as series-connected,parallel connections are also possible using a SELS 204. Further, a SELS204 or FELS 300 may be used to connect the bracket 108 to a groundplane,such as a proximate PCB groundplane 106.

FIG. 13 is a perspective drawing illustrating some exemplary FELSvariations. The FELS 300 can be a conductive metal member that issoldered or tension mounted to a bracket or groundplane. The metal formcan be straight 1300, L-shaped 1302, or O-shaped member 1304. Othershapes, or combinations of shapes are possible. Some shapes aredependent upon the surrounding area available. In addition, the FELS maybe a wire 1306, a fastener, such as screw 1308, conductive pillow(gasket) 1312, or a conductive element, such as a conductive trace orpaint 1310 formed on a PCB or housing. These are just a few examples ofFELS elements. Any element capable of conducting an electrical currentis potentially capable of acting as a FELS.

FIG. 14 is a schematic block diagram of the present invention portablewireless telephone communications device with a reconfigurable radiationdesensitivity bracket. The device 1400 comprises a telephone transceiver1402 and an antenna 1404 connected to the transceiver 1402. The portabledevice 1400 includes an electrical circuit 1406 having a groundplane1408. A reconfigurable radiation desensitivity bracket 1410 is coupledto the groundplane 1408. As in the more generic wireless devicedescribed in FIG. 1, the portable device electrical circuit 1406 may becomponents mounted on a printed circuit board (PCB), a display, aconnector, or a keypad. The details of bracket 1410 are essentially thesame as the brackets described in FIGS. 1 through 13 and 18, above, andwill not be repeated in the interest of brevity.

FIG. 15 is a schematic block diagram of the present invention wirelesscommunications base station with a reconfigurable radiationdesensitivity bracket. The base station 1500 comprises a telephonetransceiver 1502 and an antenna 1504 connected to the transceiver 1502.In this case, two antennas marked 1504 are shown. The base station 1500also includes an electrical circuit 1506 having a groundplane 1508. Areconfigurable radiation desensitivity bracket 1510 is coupled to thegroundplane 1508. As in the more generic wireless device described inFIG. 1, the base station electrical circuit 1506 may be componentsmounted on a printed circuit board (PCB), a display, a connector, or akeypad. The details of bracket 1510 are essentially the same as thebrackets described in FIGS. 1 through 13 and 18, above, and will not berepeated in the interest of brevity.

Functional Description

FIGS. 16A and 16B are diagrams illustrating the present inventionbracket redistributing radiation-induced current flow in a groundplane.The vertical dimension illustrates current flow (I). The current throughan area (unit²) is one possible measure of current distribution, forexample, A/in². However, other measurements of current or currentdistribution can be used to illustrate the invention. In FIG. 16A, arelatively high current flow in shown in one particular region as aresult of a source radiating at 890 MHz. In response to enabling thebracket 108, the current flow is redistributed, as shown in FIG. 16B.The bracket may be considered frequency reconfigurable, as a differentelectrical length may be used for different radiated frequencies.Alternately, the bracket may be considered space-reconfigurable, as itcan be used to redistribute current flow to different regions of thegroundplane. For example, the bracket 108 may be tuned to redistributecurrent (as shown in FIG. 16A) after device is moved near a proximateobject, to create the current pattern shown in FIG. 16B.

FIG. 17 is a flowchart illustrating the present invention method forreconfigurable radiation desensitivity in a wireless communicationsdevice. Although the method is depicted as a sequence of numbered stepsfor clarity, no order should be inferred from the numbering unlessexplicitly stated. It should be understood that some of these steps maybe skipped, performed in parallel, or performed without the requirementof maintaining a strict order of sequence. The method starts at Step1700.

Step 1702 generates a radiated wave at a first frequency. Alternatelystated, Step 1702 transmits at a first frequency. Step 1704 in responseto generating the radiated wave at the first frequency, creates amaximum current per units square (I/units²) through a minimal area of anelectrical circuit groundplane. That is, current flow is induced as aresult of the wave radiated in Step 1702. Step 1706 generates a radiatedwave (transmits) at a second frequency. Alternately stated, the wirelessdevice changes the frequency of transmission between Steps 1702 and1706. Step 1708, in response to generating the radiated wave at thesecond frequency, maintains the maximum I/units² through the minimalarea of the groundplane. Alternately stated, with respect to agroundplane area with a predetermined (minimal) size,radiation-associated current flow is not allowed to exceed apredetermined (maximum) level.

The groundplane may be associated with an electrical circuit such ascomponents mounted on a printed circuit board (PCB), a display, aconnector, or a keypad. However, the invention is not limited to anyparticular type of electrical circuit or groundplane. The choice of thecurrent-related measurement is somewhat arbitrary, and the invention canalso be expressed in other units of measurement related to current,energy, or field strength

Typically, maintaining the maximum I/units² through the minimal area ofthe groundplane (Step 1708) includes coupling the groundplane to abracket having a selectable effective electrical length. The couplingmechanism may be transistor coupling, where the transistor acts as aswitch, buffer, current amplifier, voltage amplifier, or reactanceelement. In other aspects, the coupling mechanism is p/n junctioncoupling through a PIN diode, selectable capacitive coupling through avaractor diode or ferroelectric capacitor, variable gap coupling using aMEMS, or mechanically bridging through a switch or MEMS. The sameanalysis applies to Step 1704.

In one aspect, Step 1708 (or Step 1704) additionally couples thegroundplane to a bracket with a fixed physical length section to providea combined effective electrical length responsive to the fixed physicallength and the selectable effective electrical length. Further, thegroundplane may be coupled to a bracket with a plurality of selectableelectrical length sections. The plurality of selectable electricallength sections may be connected in a configuration such as groundplaneconnected, series-connected, parallel-connected, or combinations of theabove-mentioned connection configurations. The invention is not limitedto any particular connection configuration type.

In another aspect, Step 1708 (Step 1704) couples the groundplane to abracket with a plurality of fixed physical length sections. Theplurality of fixed electrical length sections can be connected to aselectable electrical length section in a configuration such asconnected to the groundplane, series-connected, parallel-connected, orcombinations of the above-mentioned connection configurations.

A wireless communications device with a reconfigurable radiationdesensitivity bracket, and corresponding reconfigurable radiationdesensitivity method have been provided. Some examples of specificbracket shapes and schematic arrangements have been presented to clarifythe invention. Likewise, some specific physical implementations and usesfor the invention have been mentioned. However, the invention is notlimited to just these examples. Other variations and embodiments of theinvention will occur to those skilled in the art.

1. A wireless communications device comprising: a wireless telephonetransmitter configured to operate at a first frequency and a secondfrequency; an antenna connected to the transmitter; an electricalcircuit having a groundplane; and, a reconfigurable radiationdesensitivity bracket coupled to the groundplane and having a selectableeffective electrical length responsive to control signals to have afirst effective electrical length selected in response to thetransmitter operating at the first frequency, and a second effectiveelectrical length, selected in response to the transmitter operating atthe second frequency.
 2. The device of claim 1 wherein the electricalcircuit is selected from the group including components mounted on aprinted circuit board (PCB), a display, a connector, and a keypad. 3.The device of claim 1 wherein the selectable electrical length sectionhas a distal end, a proximal end, a control input to accept the controlsignals.
 4. The device of claim 3 wherein the bracket comprises a fixedelectrical length section having a distal end, a proximal end, and afixed physical length, the combination of the selectable electricallength section and the fixed electrical length section providing acombined selectable effective electrical length responsive to thecontrol signal.
 5. The device of claim 4 wherein the bracket includes aplurality of fixed electrical length sections.
 6. The device of claim 5wherein the plurality of fixed electrical length sections are connectedto a selectable electrical length section in a configuration selectedfrom the group including connected to the groundplane, series-connected,parallel-connected, and combinations of the above-mentioned connectionconfigurations.
 7. The device of claim 6 wherein the plurality of fixedelectrical length sections form a matrix of adjoining conductive areas;wherein a plurality of selectable electrical length sections couplebetween fixed electrical length sections; and, wherein at least one ofthe plurality of selectable electrical length sections is coupled to thegroundplane.
 8. The device of claim 4 wherein the fixed electricallength section is an element selected from the group including a wire,conductive paint, conductive trace, conductive pillow, fastener, and amember formed straight, L-shaped, O-shaped, and combinations of theabove-mentioned forms.
 9. The device of claim 4 further comprising: ahousing surrounding the electrical circuit; and, wherein the fixedelectrical length section is a conductive element formed on the housingand coupled to the groundplane.
 10. The device of claim 4 wherein thefixed electrical length section is a conductive trace formed on theelectrical circuit.
 11. The device of claim 4 wherein the electricalcircuit is a liquid crystal display (LCD); wherein the bracket includes:a selectable electrical length section coupling between fixed electricallength sections; and, a plurality of fixed electrical length sectionsforming perimeter regions around the LCD.
 12. The device of claim 3wherein the bracket includes a plurality of selectable electrical lengthsections.
 13. The device of claim 12 wherein the plurality of selectableelectrical length sections are connected in a configuration selectedfrom the group including connected to the groundplane, series-connected,parallel-connected, and combinations of the above-mentioned connectionconfigurations.
 14. The device of claim 3 wherein the selectableelectrical length section is selected from the group including a FET,PIN diode, ferroelectric capacitor, varactor diode, andmicroelectromechanical system (MEMS) switch.
 15. The device of claim 3further comprising: a desensitivity control circuit having an input toaccept frequency selection commands and an output connected to theselectable effective length sections, supplying control signals inresponse to the frequency selection commands.
 16. The device of claim 1wherein the transmitter is a wireless telephone transmitter.
 17. Aportable wireless telephone communications device with a reconfigurableradiation desensitivity bracket, the device comprising: a telephonetransceiver; an antenna connected to the transceiver; an electricalcircuit having a groundplane; and, a reconfigurable radiationdesensitivity bracket coupled to the groundplane and responsive tocontrol signals to vary current flow through the groundplane inaccordance with a frequency of operation of the telephone transceiver.18. The portable device of claim 17 wherein the electrical circuit isselected from the group including components mounted on a printedcircuit board (PCB), a display, a connector, and a keypad.
 19. Theportable device of claim 17 wherein the bracket includes a selectableelectrical length section having a distal end, a proximal end, a controlinput to accept control signals, and a selectable effective electricallength responsive to the control signals.
 20. The portable device ofclaim 19 wherein the bracket further includes a fixed electrical lengthsection having a distal end, a proximal end, and a fixed physicallength; and, wherein the combination of the selectable electrical lengthsection and the fixed electrical length section provides a combinedselectable effective electrical length responsive to the control signal.21. A wireless communications base station with a reconfigurableradiation desensitivity bracket, the base station comprising: a basestation telephone transceiver; an antenna connected to the transceiver;an electrical circuit having a groundplane; and, a reconfigurableradiation desensitivity bracket coupled to the groundplane andresponsive to control signals to vary current flow through thegroundplane in accordance with a frequency of operation of the basestation telephone transceiver.
 22. The base station of claim 21 whereinthe bracket includes a selectable electrical length section having adistal end, a proximal end, a control input to accept control signals,and a selectable effective electrical length responsive to the controlsignals.
 23. The base station of claim 22 wherein the bracket furtherincludes a fixed electrical length section having a distal end, aproximal end, and a fixed physical length; and, wherein the combinationof the selectable electrical length section and the fixed electricallength section provides a combined selectable effective electricallength responsive to the control signal.
 24. A wireless communicationdevice comprising: a wireless transceiver; an antenna connected to thetransceiver and comprising a groundplane; and a reconfigurable radiationdesensitivity bracket coupled to the groundplane and responsive tocontrol signals to vary current flow through the groundplane inaccordance with a frequency of operation of the wireless transceiver.25. The wireless communication device of claim 24 wherein the brackethas a selectable effective electrical length responsive to the controlsignals to have a first effective electrical length in response to thetransceiver operating at a first frequency and a second effectiveelectrical length, selected in response to the transceiver operating ata second frequency.
 26. A wireless communications device comprising: atransmitter; an antenna connected to the transmitter; a liquid crystaldisplay (LCD) having a groundplane; and a reconfigurable radiationbracket coupled to the groundplane and comprising: a plurality of fixedelectrical length sections forming perimeter regions around the LCD; anda selectable electrical length section having a selectable effectiveelectrical length responsive to a control signal, a distal end, aproximal end, and a control input to accept the control signal, thecombination of the selectable electrical length section and the fixedelectrical length sections providing a combined selectable effectiveelectrical length responsive to the control signals.